Gastrointestinal decontamination after poisoning. Where is the science?

Effect of deferasirox on iron absorption in a randomized, placebo-controlled, crossover study in a human model of acute supratherapeutic iron ingestion

STUDY OBJECTIVE

In 2005, the Food and Drug Administration approved deferasirox as an oral iron chelating agent for chronic iron overload. To determine usefulness in management of acute iron ingestion, we study the effect of orally administered deferasirox in healthy human adults.

METHODS

A double-blinded, placebo-controlled, randomized, crossover study of 8 healthy human volunteers was conducted. Subjects ingested 5 mg/kg of elemental iron in the form of ferrous sulfate. One hour after iron ingestion, subjects were randomized to receive 20 mg/kg of deferasirox or placebo. Serial iron levels were then obtained. A 2-week washout was used between study arms. The paired t test was used to compare area under time-concentration curves from baseline to both 12- and 24-hour iron levels between groups.

RESULTS

Baseline serum iron levels were similar in the 2 groups. Deferasirox significantly reduced serum iron area under concentration-time curves compared with placebo during both 1 to 12 hours and 1 to 24 hours (12 hour=577 μmol-hour/L and 392 μmol-hour/L, 95% confidence interval for the difference 15.8 to 353.0 μmol-hour/L; 24 hour=808 μmol-hour/L and 598 μmol-hour/L, 95% confidence interval for difference 54.4 to 366.7 μmol-hour/L).

CONCLUSION

Orally administered deferasirox significantly reduced serum iron levels when administered 1 hour after iron ingestion during the 12- and 24-hour periods after acute ingestion of 5 mg/kg of elemental iron in healthy human volunteers. Further study is required to determine optimal dosing, but deferasirox may be an important addition to current therapy for acute iron poisoning.

Effect of Oral Calcium Disodium EDTA on Iron Absorption in a Human Model of Iron Overdose

OBJECTIVE

Anecdotal case reports and animal models have suggested that the administration of CaNa2EDTA (EDTA) may be effective in reducing the absorption of iron after an oral iron overdose. We designed this study to determine the effect of orally administrated EDTA with or without activated charcoal (AC) on iron absorption after a mild iron ingestion in healthy human volunteers.

METHODS

A randomized, crossover study was conducted in eight healthy human volunteers. All subjects ingested 5 mg/kg of elemental iron in the form of ferrous sulfate. One hour post ingestion, subjects were randomized to receive 35 mg/kg EDTA, EDTA plus 50 grams of AC, or water. Serial iron levels were obtained at baseline and every hour for the first 6 hours, then at 8, 12, and 24 hours. A 2-week washout was used between study arms. The Kruskal-Wallis test was used for the following comparisons between treatment groups: baseline serum iron levels, area under time-concentration curves (AUCs) from baseline to 12 hours and baseline to 24 hours, and peak iron levels.

RESULTS

Baseline serum iron levels did not differ among the three treatment groups (p = 0.844). AUCs were not different among groups (p = 0.746 for 12 hr, p = 0.925 for 24 hr). AUC medians (with 95% binomial confidence bounds) for control, EDTA, EDTA + AC groups, respectively, for 12 hr were: 2813 (2298, 3561), 2570 (1669, 3476), and 2654 (2125, 3600); and for 24 hr were: 4083 (3488,5314), 4139 (2666, 5547), and 4274 (3336, 5577). Peak serum iron levels did not differ among treatment groups (p = 0.481). Peak iron level medians in microg/dL (with 95% binomial confidence bounds) were for control: 329 (253, 382), for EDTA: 271 (184, 375), and for EDTA + AC: 285 (229, 352).

CONCLUSION

Orally administered EDTA did not significantly reduce iron absorption when administered 1 hour post iron ingestion during the 12 or 24-hour period following the ingestion of 5 mg/kg of elemental iron in healthy human volunteers.

The hazards of gastric lavage for intentional self-poisoning in a resource poor location

OBJECTIVE

The 10-20% case fatality found with self-poisoning in the developing world differs markedly from the 0.5% found in the West. This may explain in part why the recent movement away from the use of gastric lavage in the West has not been followed in the developing world. After noting probable harm from gastric lavage in Sri Lanka, we performed an observational study to determine how lavage is routinely performed and the frequency of complications.

CASE SERIES

Fourteen consecutive gastric lavages were observed in four hospitals. Lavage was given to patients unable or unwilling to undergo forced emesis, regardless of whether they gave consent or the time elapsed since ingestion. It was also given to patients who had taken non-lethal ingestions. The airway was rarely protected in patients with reduced consciousness, large volumes of fluid were given for each cycle (200 to more than 1000 ml), and monitoring was not used. Serious complications likely to be due to the lavage were observed, including cardiac arrest and probable aspiration of fluid. Health care workers perceived lavage as being highly effective and often life-saving; there was peer and relative pressure to perform lavage in self-poisoned patients.

CONCLUSIONS

Gastric lavage as performed for highly toxic poisons in a resource-poor location is hazardous. In the absence of evidence for patient benefit from lavage, (and in agreement with some local guidelines), we believe that lavage should be considered for few patients - in those who have recently taken a potentially fatal dose of a poison, and who either give their verbal consent for the procedure or are sedated and intubated. Ideally, a randomized controlled trial should be performed to determine the balance of risks and benefits of safely performed gastric lavage in this patient population.

Emergency visits for childhood poisoning: a 2-year prospective multicenter survey in Spain

OBJECTIVES

To describe the characteristics of childhood poisoning leading to consultation to 17 pediatric emergency departments in Spain.

METHODS

During a 2-year period (January 2001 to December 2002), accompanying people of 2157 children with acute intoxication who visited consecutively at the emergency room were prospectively surveyed.

RESULTS

Childhood poisoning accounted for 0.28% of all emergency visits during the study period. The median (interquartile range, 25th-75th percentile) age was 24 months (22-60 months); 67% of children were younger than 4 years. Drug ingestion was involved in 54.7% of cases (paracetamol was the most frequent drug), domestic products in 28.9%, alcohol in 5.9%, carbon monoxide in 4.5%, and illicit drugs in 1.5%. A total of 61.3% of patients were admitted within 1 hour after exposure to the toxic substance, and 10.3% had been already treated before arrival; 29.1% of patients were referred for clinical manifestations which were mostly neurological symptoms. Laboratory tests and other investigations were performed in 40.7% of cases. Gastrointestinal decontamination was used in 51.7% of patients, with activated charcoal in 32.3%. Treatment varied significantly according to the individual hospitals. A total of 83.3% of patients were treated as outpatients, 15.2% were hospitalized, and 1.5% were admitted to the intensive care unit. One 11-month-old boy with carbon monoxide intoxication died. Six patients had permanent sequelae (esophageal stenosis in 5 and partial blindness in 1).

CONCLUSIONS

Young children who accidentally ingested drugs and, less frequently, domestic products accounted for most cases of intoxication who presented at the pediatric emergency department.

Eficacia y seguridad de la descontaminación digestiva en la intoxicación medicamentosa aguda

BACKGROUND AND OBJECTIVE

Gut decontamination (GD) may be used as a treatment for acute therapeutic drug overdose (ATDO) to reduce the absorption of the drug and thereby avoid the presence or worsening of signs and symptoms of intoxication. The objective of this study was to assess the efficacy and safety of GD in ATDO patients.

PATIENTS AND METHOD

A 4-month prospective observational study was designed to include all patients admitted to the emergency department due to an ATDO. On admission, epidemiological data, vital signs and physical examination results were all recorded and a blood sample was taken for toxicological analysis. An algorithm was used to determine the GD method to be applied. A clinical reassessment was made at 3-6 hours and a further sample was taken for toxicological analysis. Patients were followed until hospital discharge, with all possible adverse events due to GD being recorded.

RESULTS

Ninety-four patients were included. GD was indicated in 60 patients (63.8%): 3.3% received ipecacuana syrup, 8.3% gastric lavage, 21.6% gastric lavage followed by activated charcoal and 71.6% oral activated charcoal alone. The clinical state worsened in 19.1% of patients, usually on the basis of a diminished consciousness. Adverse events attributable to GD were observed in 8.3% of patients. A toxicological analysis was made in 50 patients and in 42% of them, drug concentrations were higher at 3 or 6 hours than on admission. An analysis of the method of decontamination used showed that the procedure recommended by the algorithm was applied in 70 patients (group A) while in the remaining 24 (group B) another decontamination technique was used. Clinical deterioration was seen in 14.3% of patients in group A and 33.3% in group B (p = 0.041). There was a favourable evolution of the analytic curve in 63.9% patients in group A and 42.9% in group B (p = NS); severe adverse events attributable to GD were suffered by 2.4% patients in group A and 11.1% in group B (p = NS).

CONCLUSIONS

The efficacy and safety of GD in ATDO increases in patients in whom the decision-making algorithm is applied. However, this does not prevent clinical deterioration or continued drug absorption in all cases and may be accompanied by adverse events.

Evaluation of the time frame for home ipecac syrup use when not kept in the home

INTRODUCTION

The home administration of ipecac syrup remains a recommendation in some guidelines for the management of specific pediatric poisonings. A common challenge for poison specialists is how to approach the situation when ipecac syrup is indicated but not kept in the home. This study examines whether or not ipecac syrup can be administered and produce timely emesis in this situation.

METHODS

Over a 6-month period, a prospective observational study was undertaken to determine if ipecac syrup can be administered in a timely manner when it is indicated but not available in the home. Cases where ipecac syrup was indicated but not kept in the home were included if parents stated that they could obtain ipecac within 15 minutes. Timely administration and the onset of emesis were defined as < 30 min and < 60 min, respectively.

RESULTS

During our study 14,603 human exposures were evaluated; ipecac syrup was recommended by a poison specialist in 75 cases, and 25 of these were included in our study. Ages ranged from 1 to 6 years. The mean time to administration of ipecac from exposure time was 40 min (SD +/- 14 min). Administration of ipecac syrup occurred in < 30 min in 20% of the cases. The mean time to first emesis from exposure was 58 min (SD +/- 13). Initial emesis occurred in < 60 min in 36% of the cases.

CONCLUSIONS

Ipecac syrup was rarely recommended by our center and was frequently unavailable when it was recommended. Ipecac syrup often could not be administered in a timely manner because it was not kept in the home. Parents of pediatric patients who have a significant ingestion should not be referred to purchase ipecac syrup.

Activated charcoal forms non-IgE binding complexes with peanut proteins

BACKGROUND

Conventional management of peanut-induced anaphylaxis is composed of administration of epinephrine, antihistamine, and steroid and stabilization of airway, ventilatory, and circulatory function. Therapies directed toward slowing or preventing further absorption of peanut protein from the gastrointestinal tract after accidental ingestion have not been a routine part of management.

OBJECTIVE

The purpose of this study was to determine the ability of activated charcoal to complex with peanut protein, thereby preventing its binding to either peanut-specific IgE or peanut-specific IgG.

METHODS

Peanut protein was coincubated with micronized activated charcoal suspension at pH 3.5 or 7.4. Peanut protein complexed with charcoal was removed by centrifugation. Binding of residual peanut protein to peanut-specific IgG was measured by a sandwich ELISA assay. Also, ability of uncomplexed peanut protein to bind to peanut-specific IgE was determined by Western blot and by skin prick testing in subjects with peanut allergy.

RESULTS

Activated charcoal (AC) formed complexes with peanut protein, effectively competing for binding with peanut-specific IgG in a sandwich ELISA assay. AC complexed efficiently with peanut protein at both neutral and acidic pH in as little as 60 seconds. AC was also able to remove IgE-binding peanut allergens from solution as determined by Western blot and by skin prick testing in subjects with peanut allergy. A ratio of 200 mg of AC to 1 mg peanut protein was required for complete removal of peanut protein from solution. AC was able to complex with peanut protein within food matrices such as ice cream and chocolate.

CONCLUSION

The data presented herein show that AC removes both IgE-binding and IgG-binding peanut proteins from solution rapidly at both neutral and acidic pH. These data suggest that administration of AC may be useful as an adjunct to slow or to prevent further absorption of peanut protein from the gastrointestinal tract after accidental ingestion by individuals with peanut allergy.

Efficacy of superactivated charcoal administered late (3 hours) after acetaminophen overdose

The purpose of this study was to investigate the effect of superactivated charcoal (SAC) given late after a drug overdose. Acetaminophen was chosen as our overdose drug because it has relatively few side effects, serum levels are easily attainable and measurable, and it is generally a common drug overdose. Forty-six healthy adult volunteers participated in this randomized, controlled study. Acetaminophen was administered the morning after an overnight fast. Thirteen participants received 2000 mg acetaminophen and the remaining 33 received 3000 mg. After 3 hours, half of the participants (22 of 46) received 75 g of SAC (Requa, Greenwich, CT) orally as a slurry in 8 oz of apple juice. Serum acetaminophen levels were measured at 4 and 7 hours after the initial acetaminophen administration. There were significantly lower uncorrected and corrected acetaminophen levels in the SAC group compared with the control group at both 4 and 7 hours after ingesting acetaminophen. This randomized human experimental design trial demonstrates some detoxification benefit in administering superactivated charcoal 3 hours after an overdose.

Extracorporeal therapies for acute intoxications

Intoxications frequently perturb acid-base and electrolyte status, intravascular volume, and renal function. In selected cases, extracorporeal techniques effectively restore homeostasis and augment intoxicant removal. The use of 4-methylpyrazole, an inhibitor of alcohol dehydrogenase, is a new and effective treatment for patients exposed to toxic alcohols. In this section, practical approaches to commonly encountered intoxicants and the use of extracorporeal techniques are critically reviewed.

Decontamination strategies

The appropriate use of decontamination techniques may prevent or limit the adverse effects of many toxic substances. No one approach to decontamination is appropriate in all situations. Decontamination procedures should be designed to suit both the individual patient and the circumstances of exposure. Inappropriate use of decontamination procedures may complicate the successful treatment of toxicosis and negatively impact case outcome.

The role of activated charcoal and gastric emptying in gastrointestinal decontamination: a state-of-the-art review

Gastrointestinal decontamination has been practiced for hundreds of years; however, only in the past few years have data emerged that demonstrate a clinical benefit in some patients. Because most potentially toxic ingestions involve agents that are not toxic in the quantity consumed, the exact circumstances in which decontamination is beneficial and which methods are most beneficial in those circumstances remain important topics of research. Maximum benefit from decontamination is expected in patients who present soon after the ingestion. Unfortunately, many overdose patients present at least 2 hours after taking a medication, when most of the toxin has been absorbed or has moved well into the intestine, beyond the expected reach of gastrointestinal decontamination. Decontamination probably does not contribute to the outcome of many such patients, especially those without symptoms. However, if absorption has been delayed or gastrointestinal motility has been slowed, activated charcoal may reduce the final amount absorbed. The use of activated charcoal in these cases may be beneficial and is associated with few complications. Therefore, administration of activated charcoal is recommended as soon as possible after emergency department presentation, unless the agent and quantity are known to be nontoxic, the agent is known not to adsorb to activated charcoal, or the delay has been so long that absorption is probably complete. The use of gastric emptying in addition to activated charcoal has generated intense debate. Several large comparative studies have failed to demonstrate a benefit of gastric emptying before activated charcoal. Because complications of such 2-step decontamination include a higher rate of intubation, aspiration, and ICU admission, gastric emptying in addition to activated charcoal cannot be considered the routine approach to patients. However, there are several infrequent circumstances in which the data are inadequate to accurately assess the potential benefit of gastric emptying in addition to activated charcoal: symptomatic patients presenting in the first hour after ingestion, symptomatic patients who have ingested agents that slow gastrointestinal motility, patients taking sustained release medications, and those taking massive or life-threatening amounts of medication. These circumstances represent only a small subset of ingestions. In the absence of convincing data about benefit or lack of benefit of gastric emptying for these patients, individual physicians must act on a personal valuation: Is it better to use a treatment that might have some benefit but definitely has some risk or not to use a treatment that has any risk unless there is proven benefit?

The potential role of prehospital administration of activated charcoal

OBJECTIVES

Activated charcoal is now the mainstay of non-specific treatment for self poisoning in accident and emergency (A&E) departments and should be administered within one hour of ingestion of an overdose. This study aimed to investigate if compliance with treatment guidelines may be improved by the prehospital administration of activated charcoal.

METHOD

Ambulance report forms and case notes were reviewed in all patients presenting to A&E by ambulance after self poisoning. Information was gathered using a standardised abstraction form. The times collected were: time of ingestion, time of call to ambulance control, time picked up, time of arrival in A&E and time seen by doctor.

RESULTS

201 patient records were reviewed. Twenty six were excluded because of incomplete data on report forms or case notes. The median time between ingestion and pick up by an ambulance crew was 77 minutes. This compares with a median of 140 minutes for the time to assessment by medical staff. Seventy three patients were picked up by an ambulance within one hour of overdose, only 11 (15%) of these were seen by medical staff within an hour of ingestion. Forty nine of these 73 patients would have been suitable candidates to receive activated charcoal.

CONCLUSIONS

The prehospital administration of charcoal provides an opportunity to comply with international guidelines on reducing the absorption of a potentially fatal overdose. The administration of charcoal results in few side effects provided the patient can adequately protect their airway and ambulance staff could be trained in its use. Further studies would be necessary to investigate if this would effect clinical outcome.

5-Year analysis of mushroom exposures in California

OBJECTIVE

To evaluate outcomes following toxic mushroom ingestions.

DESIGN

Retrospective data analysis.

METHODS

We analyzed American Association of Poison Control Center data for California from 1993 through 1997.

RESULTS

A total of 6,317 exposures occurred during the study period. Most (n = 6,229 [99.7%]) were acute exposures, and the rest (0.3%) were chronic; 87.6% (n = 5,536) were unintentional. Most (n = 4,235 [67.0%]) were in children younger than 6 years, and of these, only 6.0% experienced any clinical effects. The most common symptoms in patients aged 6 years and older were vomiting in 588 patients (28.2%), nausea in 307 patients (14.7%), diarrhea in 263 patients (12.6%), and abdominal pain in 221 patients (10.6%). No effects were seen in 3,131 (49.6% of all patients). Major effects were seen in only 17 patients (0.3%). Only 61 patients (1.0%) were admitted to a critical care unit. Death occurred in a 32-year-old adult who ate foraged mushrooms. Of all patients, 1,375 (21.8%) received no therapy or were observed only.

CONCLUSIONS

Most mushroom exposures were acute and unintentional and occurred in children younger than 6 years. Major toxic reactions or death was uncommon.

Indications for, techniques of, complications of, and efficacy of gastric lavage in the treatment of the poisoned child

Gastrointestinal decontamination is central to the care of poisoned patients, and gastric lavage is one common method for gastrointestinal decontamination. Gastric lavage in pediatric patients should be limited to children who present shortly after a potentially life-threatening ingestion. The routine use of gastric lavage has recently been questioned because of limited outcome data and increased morbidity. If gastric lavage is deemed necessary, proper positioning of the patient and strict attention to appropriate technique are essential to avert complications.

Past, present, and future role of ipecac syrup

Historically, ipecac syrup has played a principal role in the management of acute poisonings and overdoses. Presently, its role largely has been relegated to prompt decontamination of acute childhood poisonings for which emesis is not contraindicated. However, even this specific and limited role has undergone rigorous re-evaluation, and many toxicologists have discouraged against its use in any circumstance. This article reviews the history, scientific literature, and public health implications of ipecac syrup that support its present clinical application.